Refrigerated containers are used in the transportation industry to carry cargo that is temperature and/or time sensitive. Perishable cargo such as fresh, chilled or frozen food products as well as products such as pharmaceuticals, blood plasma, film, batteries and the likes, are also commonly carried in such containers.
Refrigerated containers, or reefers, consist of two main parts—the box/container and the refrigerated machinery. The box is usually similar in shape and size to commonly seen cargo containers, i.e., 20 or 40 feet long by 8 feet wide by 8 feet tall is typical. The box is typically made with a layer of insulating material sandwiched between an outer painted steel shell and an inner stainless steel shell that makes up the walls, floor and roof. At one end of the container are two interlocking doors and at the other end, embedded in the end wall, is the reefer machinery.
The reefer machinery consists of two main parts—the refrigeration apparatus (motor, compressor, refrigerant, evaporators, fans, etc.) and the control computer (or controller, micro or microprocessor). This machinery is accessible on the outside of the container and based on manually inputted settings to the micro (through a keypad or connected handheld device or PC), the machinery switches on and off and blows cold air into the reefer box. When the temperature that was inputted is satisfied, i.e., when the box reaches the required temperature, the micro, based on feedback from a number of sensors embedded in the reefer machinery, will close down the cold air delivery. If the temperature starts to deviate from the set temperature the micro will start up the machinery again and get the temperature within the desired range. It is, in many ways, identical in operation to a common domestic refrigerator—constantly switching on/off to maintain the proper settings.
For the supplier, shipper, agent, shipping line and consignee, it is of great importance that such cargo is maintained within certain temperature or other environmental constraints throughout the shipping process from packing to unpacking and that such cargo is delivered in a timely manner.
Those responsible for the shipping and transportation of such goods go to considerable lengths to try to ensure that the cargo is maintained and delivered to the shipper's and consignee's satisfaction. Typical measures include computer systems that track the manual entry of each container number at key points throughout the transportation chain. For example, these could be at the gate in transaction at the originating port for an export loan, at loading onto the ship, at unloading from ship, at gate out from destination port and in some cases at customer delivery. That is, at each of these points, someone (or in some cases optical recognition cameras) records the container number and has it entered into a software system which would keep track of each such entry so that at any point in the process, a shipper, consignee or other interested party could request an update on the progress of the goods.
In addition, with refrigerated containers, such interested parties may also inquire as to the environmental status of the goods, e.g., is the temperature at the requested levels and are there any alarms and/or other notable exceptions. To answer these questions and ensure that conditions are as requested, the shipping line or transportation company or container port or other container operator will periodically physically check the status of the reefer apparatus and read temperatures, check the machine for alarms and make adjustments as necessary.
This is achieved through the use of personnel on the ground at each facility or on board ships that climb ladders or racks and manually read and record the data displayed on the reefer's on-board microprocessor.
However, there are commercial, technical and operational weaknesses with the process described above for monitoring the health of the cargo in the reefers and maintaining the condition of the reefer machinery. In particular, the following are some of the weaknesses as seen from the perspective of the responsible party at the time of storage or transition, e.g. port operator, yard operator and ship operator:                High Labor expense—It's currently expensive to continually have highly-paid yard laborers check reefer status, set temperatures, pre-trip containers for use, sort alarms from good reefers and report back results. In addition, during off hours, when monitoring is still required regardless of the facility being open for business or not, this labor cost can increase dramatically with double or triple time wages.        Spoiled/damaged cargo—without continuous and real time visibility as to the condition of the cargo, cargo loss can result from unattended alarm conditions or other unscheduled operational changes.        Missed billing—The yard operator/owner can derive revenue for each reefer handled as well as the time spent in their yard and any temperature resets, powering the reefer on/off, alarms resets or additional readings for special cargo or customer requests. Currently with the manual process, it is often the case that these revenue points are not recorded correctly, or at all, and thus the yard operator is missing billing opportunities.        Customer Service—Often with special cargo, e.g. film, blood plasma, etc, the cargo owner/agent will call the yard/ship/facility to request manual intermediate readings from the reefer micro to gain assurance that the cargo is maintained correctly. It is currently very labor intensive, slow, expensive and disruptive to provide such customer feedback regarding the state of the cargo in the reefer while in their custody.        Lack of Visibility—There is a lack of real time visibility for the cargo owner and container operator alike.        Blind Spots—There are a number of transition phases where the reefer is in transition from an area where monitoring systems/processes exist (as described above) through which no system or personnel exist or can be easily deployed to ensure that the cargo is maintained as desired. In these transition phases, should an alarm occur or a reefer get out of temperature or some other nonconforming event happen, there is typically no way for a yard operator to know this, and thus potential exists for damage/spoilage to occur. Some of the typical transitions where this can occur is in the hand off from the yard to the ship or the ship to the yard or the yard to the trucker or rail where time can elapse and no monitoring takes place. Not having a defined start or stop point to these transition phases creates an indefinable “non-monitored”period which introduces risk.        
There are some existing solutions that attempt to address these problems. Reefer power line technology provides for a radio frequency carrier applied over the power cord to a reefer that allows communications with the control system. This solution requires the permanent installation, usually at the time of reefer manufacture, of a power line modem (sometimes called an RMU). It also requires a significant infrastructure be installed on the ship and in ports and yards. Whilst widely installed on ships, this solution is much less prevalent on reefer containers and very few ports have installed the solution due to its expense and lack of overall ease of use with respect to the software and lack of integration with yard management systems. Further, suppliers of this technology are limited.
Other companies provide for wireless/satellite tracking solutions. These companies provide devices that are fitted with local RF, cellular or satellite radios with some form of power supply (battery, solar or other) that are typically permanently attached to the reefer and in some cases hard wired to the reefer's microprocessor. Furthermore, since reefers only pass through facilities, ports, yards, and vessels, these operators do not typically own the reefers and may not have permission to permanently attach any additional hardware.
Traditional solutions 10, such as shown in FIG. 1(a) and FIG. 1(b), do not lend themselves to fast installation or temporary usage since they require considerable effort in wiring and mounting and do not have the battery capacity to work when the reefer is not running for any practical length of time. These existing solutions are typically permanently mounted on the reefer and require hard wiring into the reefer control panel which involves opening the door, screwing down the wires on terminals, finding a mounting location for the device, finding a path for antenna wiring and finding a location on the outside of the panel for the antenna.
Finding a location for the traditional tracking device is very challenging since it is usually quite large and the antennas are separate items wired to the device. These traditional solutions are generally hidden inside the reefer machinery in such a way as to protect and store them safely. Further, traditional solutions are also typically orders of magnitude, more expensive to install and maintain and require subscription services with public wireless or satellite companies to gain continual reporting. It also requires all storage facilities to be on the same overall network.
Therefore, there is a significant need in the market for a device that can provide for continuous monitoring of mobile refrigerated containers without the drawbacks of the prior art as set out above.